Voyager finds unknown region at the solar system’s edge

NASA’s Voyager 1 spacecraft, now 122 times the distance between the Earth and the sun away from home, has entered unknown spaceat the solar system’s edge.

Scientists have characterized this unexpected region of space as a “magnetic highway” for charged particles, where there are both particles from the sun as well as cosmic particles from outside the solar system.

During the last couple of months scientists have seen several characteristic signs that the spacecraft had reached the edge of the solar system, and perhaps even exited it. Most notably they saw a rise in cosmic ray particles (from outside the solar system) and a decrease in protons originating from the sun (pink and magenta in the lower graphic).

As yet another indication that the spacecraft had departed the solar system, the velocity of the solar wind has also slowed down to zero. This was shown, amazingly, after scientists commanded the 35-year-old craft from 11 billion miles away to perform a delicate, 70-degree turn to measure the solar wind in the up and down directions.

But that’s not the entire story.

To confirm that Voyager 1 has reached interstellar space scientists have been looking for a change in the direction of the magnetic field. The graphic below, which starts on Aug. 22, shows a jump the intensity of the magnetic field Aug. 25 when scientists think Voyager 1 permanently entered a new solar system region they are calling the “magnetic highway.”

Voyager 1 Magnetic Field Strength and Direction. (NASA)

This region of space was not predicted, but because there was not a major change in the magnetic field’s direction to become oriented more in a north-south direction, scientists still don’t think Voyager has reached interstellar space.

“If we would have only looked at particle data alone, we would have said we’re out of the solar system,” said Stamatios (Tom) Krimigis, Voyager’s low-energy charged particle principal investigator. ”But nature is very imaginative, and Lucy pulled up the football again.”

Voyager has enough power to keep going until about 2025. Scientists said today they expect Voyager to break into interstellar space well before then.